I can confirm the crash with the "Kings, Queens and Pawns" book. I have created an issue on the tracker and attached the epub.

In the future, if you find a bug or want to request a feature, please create an issue like I did. If it's a bug, write the procedure that replicates it and attach the file in which it can be replicated.

This makes this go much smoother. Your bug will be analyzed, and if it's confirmed, I'll try to fix it as soon as possible.